CdF2 crystals doped with fluorides of rare earth metals and manganese with free carrier concentration of the order of 1 to 2 × 1017 cm−3 are investigated. It is shown that after consecutive stripping of the catholyte and anolyte surfaces the area of the decomposition of CdF2 is some microns thick and in the bulk of the wafer the degree of the decomposition consequently changes. The electroluminescence of the wafers after electrochemical processes is of the same order as that of the untreated CdF2 crystals. In conclusion it is stated that n‐type CdF2 crystals exhibit electroluminescence degradation during electric charge transport. It seems that not only the changes in the chemical composition influence the luminescence duration. The degradation is rather caused by the decrease in conductivity of interface of CdF2–metal electrodes.